Kienbock's Disease follows a specific progressive pattern which is formed into stages.

Initially, in the early phases of Kienbock's Disease, the changes are localized to the lunate. In these phases, radiographs reveal increased density, which progresses to lunate collapse. In the later phases, the pathology involves the mechanical structure and kinematics of the wrist, not just the lunate. In the more severe disease, the proximal widens, and rotatory instability of the scaphoid and diffuses degenerative changes occur.

Stage I

In this Stage, radiographs are normal except for the possibility of a linear or compression fracture that may be shown on tomography. In this phase, bone scan usually is abnormal, and magnetic resonance imaging (MRI) is currently diagnostic.

It should be noted that MRI was not available for the diagnosis of this disorder when this classification was devised. Many have suggested that Stage 0 should be added for those cases in which MRI changes are the only diagnostic clues. It should be clearly understood that these cases fit into Stage I.

Stage I was a stage awaiting a diagnostic tool. In fact, Litchman states in his paper that "radionucleide scanning in stage I may be abnormal, and refinements in current techniques may soon permit reliable early diagnosis.

Stage II

Disease in this Stage is still localized to the lunate. The size, shape, anatomic relationship, and kinematics of the carpal bones are not significally altered. The lunate has a definite increased density relative to the other carpal bones. Late in this Stage, some bone height may be lost on the radial side of the lunate fracture that may be shown on tomography. In this phase, bone scan usually is abnormal, and MRI is currently diagnostic.

Stage III

This Stage is the transitional one in which the disease begins to affect the carpal structure and kinematics. At this point, the lunate has collapsed in the frontal plane and elongated in the sagittal plane. The capitate begins to migrate proximally. Foreshortening of the scaphoid (the ring sign), scapholunate dissocation, and ulnar deviation of the triquetrum may or may not be present radiographically. Measurements of the carpal height ratios, or the lunar perimeter and lunate area indices, help determine the degree of carpal collapse.

This transitional Stage is divided into Stages IIIA and IIIB. In Stage IIIA, lunate collapse occurs without fixed scaphoid rotation and other secondary derangements.

Stage IV

All the findings of Stage III are present as well as generalized degenerative changes in the carpus. The surface of the adjoining bones affected resulting in generalized inter-carpal arthritis in the wrist.